New CHA/V-derived DIY standalone video synth

Discussion of modular and standalone video generating/processing techniques and associated hardware.

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rossgrady
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New CHA/V-derived DIY standalone video synth

Post by rossgrady » Sat Aug 17, 2019 8:17 pm

Hey y'all,

After building LZX Cadet series modules, a friend showed me Jonas Bers's CHA/V website, and it got my DIY energy flowing (because cheap & hacky are definitely my thing). Initially I just designed a little board so I wouldn't have to solder directly onto the little red VGA tester, but things kind of snowballed from there.

Image

There are currently two modules, as you can see. The first one has 9 square-wave oscillators, all of them syncable, 3 of them CV-able. 3 mix busses, and the ability to pass through video signal from whatever VGA source you connect -- you can use the traditional little red VGA tester that the CHA/V uses, or anything else that generates VGA.

The second module adds an on-board mic, 3 AND gates, a comparator, 2 triangle LFOs, some attenuators, some voltage sources & 2 external inputs.

All patching is done with little Dupont patch wires, similar to the Bastl Kastle or the AE modular system.

I'm calling it the ec500 system at the moment.

It works well enough that I'm prepared to sell PCBs, kits, or built units. I put up a website, 508.loopdetected.net

I'll link to a couple of YouTube videos below. A full playlist of demos is here.

i'm eager to answer any/all questions you might have!

[video][/video]

[video][/video]

[video][/video]

rossgrady
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Post by rossgrady » Sat Aug 24, 2019 1:42 pm

I did a longer video introducing some of the basics of how to patch & the types of basic things it will do:

https://www.youtube.com/watch?v=6S0duuBLhvQ

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ARC
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Post by ARC » Mon Aug 26, 2019 3:53 am

Looks good!

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lud
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Post by lud » Fri Sep 06, 2019 6:32 am

Thanks for your videos, very interesting device. Checked out your walkthrough - 9 oscillators!
Results remind me a bit of the Vidiot :party:

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lud
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Post by lud » Fri Sep 06, 2019 6:34 am

PS - chav is a very derogatory name in the UK unfortunately! :eek:

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joem
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Post by joem » Fri Sep 06, 2019 4:34 pm

lud wrote:PS - chav is a very derogatory name in the UK unfortunately! :eek:
Pretty sure that's why it was named that.

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jimboburgess
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Re: New CHA/V-derived DIY standalone video synth

Post by jimboburgess » Tue Sep 17, 2019 9:04 pm

rossgrady wrote:Hey y'all,

After building LZX Cadet series modules, a friend showed me Jonas Bers's CHA/V website, and it got my DIY energy flowing (because cheap & hacky are definitely my thing). Initially I just designed a little board so I wouldn't have to solder directly onto the little red VGA tester, but things kind of snowballed from there.

Image
very cool stuff what are the plans for the breakouts you made? Seems like a fun project.

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dComposer
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Post by dComposer » Thu Sep 26, 2019 9:11 am

Oh this is glorious! Thanks!!

rossgrady
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Re: New CHA/V-derived DIY standalone video synth

Post by rossgrady » Fri Oct 04, 2019 9:29 am

jimboburgess wrote:
very cool stuff what are the plans for the breakouts you made? Seems like a fun project.
Hey, sorry to take so long in replying -- life caught up with me!

The expansion headers carry hsync/vsync, ground, and +5v and +12v. The idea is that one shouldn't have to power each module with a separate power supply, although it remains to be seen how many of them can be powered with a single power supply without affecting their behavior.

Plans for the next expansion module(s) include more comparators, a syncable saw-to-triangle wave oscillator, maybe some fixed ramps, half- and full-wave rectifiers for frequency doubling, and ideally some source of randomness or pseudo-randomness (chaos). Right now those are 100% in my head & 0% on the breadboard, but hopefully that will change shortly! :)

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SyndieBot2000XL
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Post by SyndieBot2000XL » Tue Oct 15, 2019 11:09 am

Finished my build of this a couple days ago. Have been testing things and just kind of messing around.

I was warned, but was still not prepared for what a ballache the female pin headers were to install straight. I really had trouble until I figured out to use the faceplate as a kind of jig, clamped down with a pair of long m3 bolts, and then a male header of the appropriate length (either two or three pins) stuck through the opening in the “jig” to keep the header straight.

The SMD work was actually very easy, things are very well placed and spaced.

Now I just have to learn to drive this crazy thing. Thanks Ross! :hail:

rossgrady
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Post by rossgrady » Thu Oct 24, 2019 2:50 pm

SyndieBot2000XL wrote: I was warned, but was still not prepared for what a ballache the female pin headers were to install straight. I really had trouble until I figured out to use the faceplate as a kind of jig, clamped down with a pair of long m3 bolts, and then a male header of the appropriate length (either two or three pins) stuck through the opening in the “jig” to keep the header straight.
Yeah, I have a permanent jig that I made literally the same way, just with a 2nd mainboard with the male headers soldered on the backside. Maybe I should just ship a bunch of male 1x2 and 1x3 headers with every kit so at least ppl can replicate your strategy! :)

Glad to hear it was easy(ish) otherwise -- post back here if you get any kewl video to share!

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